Highly conductive nanocomposites based on cellulose nanofiber networks via NaOH treatments

Developing functional nanocomposites with the utilization of the sustainable natural resources (e.g. cellulose) is one most importance strategy. In this study, a novel method was developed and used to fabricate flexible conductive nanocomposite. The key innovation of this method is that carbon nanotubes (CNTs) was incorporated into cellulose nanofiber (CNF) gel which processed by alkali treatment. We found that the gelation process caused the shrinking of CNF/CNT gel-film, which result in forming a robust 3D network structure. While the shrinking attributed to constructing high density CNTs electron transport pathways and achieve improved electrical conductivity. Results clearly show that CNFs, a dispersing agent, were used to well-dispersed the CNTs in the nanocomposite. After the alkali treatments, the as-prepared CNF/CNT gel-film had a conductivity of 5.02 S/cm, which is almost 3-fold higher than the CNF/CNT film (without alkai treatment), at 20 wt% CNTs. Conductivity of the CNF/CNT gel-film was further improved to as high as 17.04 S/cm, when adding 50 wt% CNTs. Morphology investigation exhibited that CNFs and CNTs formed into a high density 3D network affording adequate electron transport pathways, and giving the gel-film remarkable electrical conductive properties. Additionally, in lights of its excellent electrical performance, low cost, and environmental friendliness, the CNF/CNT gel-film may have a promising application in the flexible electrodes and conductive papers.